1. Field of the Invention
The present invention relates to a connecting construction of a branch pipe and a connection method thereof. More particularly, the invention relates to a connecting construction of a branch pipe, which includes a branch-pipe joint fixed to an outer peripheral face of an existing pipe and attached to a passage forming member for forming, between the passage forming member and the outer peripheral face of the existing pipe, a guide passage extending from a lower portion to an upper portion of the existing pipe along a peripheral direction of the pipe, with the branch-pipe joint being oriented along a radial direction of the existing pipe so that a branching pipe portion thereof for branch-pipe connection is opened at an upper portion within the guide passage and a closing member for closing an upper through hole after formation of a lower through hole, the upper through hole being provided in an upper pipe wall of the existing pipe for forming, in a lower pipe wall of the existing pipe, the lower through hole communicated with a lower portion inside the guide passage through the branching pipe portion, with the closure of the upper through hole, communication being established between a branch pipe connected to the branching pipe portion and the existing pipe through the guide passage and the lower through hole.
2. Description of the Related Art
According to the above-noted connecting construction of a branch pipe, the branch-pipe joint forming, between this joint and the outer peripheral face of the existing pipe, the guide passage extending from the lower to upper portion of the existing pipe along the peripheral direction of the pipe is secured to the existing pipe, so that the existing pipe and the lower portion of the existing pipe are connected with each other via the guide passage in the form of a spiral passage formed by the branch-pipe joint. With this construction, in connecting the branch pipe for e.g. newly installing a fire hydrant to a water pipe as the existing pipe, substance such as sand or rust accumulated or deposited at the bottom of the water pipe may be discharged efficiently together with the flow of water discharged from the fire hydrant.
And, according to the conventional branch-pipe connecting construction, for closing the upper through hole formed in the upper pipe wall of the existing pipe, as described in e.g. the Japanese laid-open patent gazette Hei. 7-113489, a manipulator rod is attached to the closing member in the form of a plate having upper and lower flanges along the peripheral edges thereof and then this closing member is inserted into the guide passage through the branching pipe portion. Then, the closing member inserted in the guide passage is forced into the upper through hole while the position of the member is being controlled by the manipulator rod from outside the branching pipe portion, so that the peripheral edge of the upper through hole is fitted between the upper and lower flanges of the closing member, thereby fixing the closing member to the existing pipe.
According the convention described above, the closing member introduced into the guide passage is pushed into the upper through hole while being controlled in position from outside the branching pipe portion so as to be fixed to the existing pipe per se. Therefore, the precise positioning of the closing member relative to the upper through hole is difficult and the efficiency of the operation is poor.
The present invention attends to the above drawback of the conventional art and a primary object of the invention is to overcome this drawback by providing an improved branch-pipe connecting construction while facilitates the accurate positioning of the closing member to the upper through hole for improved operation efficiency, by devising improved fixing arrangement of the closing member.